Feeding mechanism for rock drills



Nov. l1, 1952 J. A. LARCEN ETAL 2,617,388

FEEDING MECHANISM FOR Rocx DRILLs Filed July 19, 1949 "42 40 27 5 36 37 FIG. 2 a r..'.'...""2..llll a 2o 32 33 26 38 Y I :mmm Y i i* l y l ll-A-l/ @f `-`17 1e 24 31 9 23 @A '5 3O4 39 21 FIG' 322 9 'l ATTORNEY Patented Nov. 11, 1952 FEEDING MECHANISM FOR ROCK DRILLS .l an August Larcn, Stockholm, and Sven Laurentius Ytterfors, Stensberg, Sweden, assignors to Aktiebolaget Atlas Diesel, Stockholm, Sweden,

a corporation of Sweden Application July 19, 1949, Serial No. 105,640

7 Claims. 1 i

This invention relates to feeding mechanisms for rock drills comprising an expansible pressure uid operated feed leg, a supporting device on said feed leg for hingedly supporting a rock drill on the feed leg, and a valve device for controlling the supply of pressure fluid to the feed leg. In such feeding mechanisms the pressure fluid, for instance compressed air, is supplied to the feed leg over a valve device separate from the control valve of the rock drill.

One object of the invention is to provide a valve device for a feeding mechanism of the type set forth, which is adjustable for different feed pressures. Another object of the invention is to provide a valve device, in which the adjustment of the valve device may be maintained irrespective of the socks to which the feeding mechanism is subjected during operation of the rock drill. A further object of the invention is to provide a valve device, which is cheap and simple in manu facture, and which is easy to assemble and to disassemble.

For these and other purposes we provide a passage in the valve device for conducting pressure fluid to the feed leg, a pressure reduction valve in said passage, a valve control member for setting said valve for different fluid pressures, and a coupling between said member and a stationary part for arresting the member in different positions of adjustment.

In the accompanying drawings one embodiment of a feeding mechanism according to the invention is illustrated by way of example. It should be understood, however, that the invention is not limited to the embodiment described hereinbelow and may be modified in several dif ferent ways within the scope of the claims.

Fig. 1 is a side elevation of the rear portion of a rock drill and a part of the feeding mechanism forming a supporting device for the rock drill. Fig. 2 is a longitudinal section through a portion of a feed leg and the valve device of a feeding mechanism according to the invention. Fig. 3 is a side elevation and partial section of a handle for the feeding mechanism forming a part of the valve device, and Fig. 4 is a section on line 4 4 in Fig. 3.

The rock drill I in Fig. 1 is provided with a feeding mechanism comprising a supporting device secured to a feed leg. The supporting device consists of a head 2, to which two side members 3 are hingedly connected by means of a bolt 4. The side members 3 are clamped to the conventional side bolts 5 of the rock drill by means 0f clamps 6 and bolts 'I. The rock drill I is consequently swingable on the bolt 4 relative to the head 2. The head 2 of the supporting device provides a socket which is secured to the eXpansible feed leg, the latter being a device separate and detachable from the drill and consisting of a pair of telescopically arranged members 8 and 9, the member 8 of which carries the head 2 as is obvious from Fig. 1. The member 9, which is illustrated partially in Fig. 2, forms a cylinder, in which a piston, not shown, provided at the end of the member 8 which also is not illustrated, is movable in conventional manner. The member which consists of a hollow rod, is provided with a passage Il) for pressure fluid opening at the end of said piston remote from a head II provided on the member 9, as is well known in the art and therefore not illustrated in the drawings. The head I I is slidable on the rod 8. The rod 8 is provided with an annular recess I2, in which the passage I 0 opens and which is enclosed by a. housing I3 forming a part of a valve device for controlling the supply of pressure fluid to the feed leg.

Pressure uid is supplied to the Valve device through a connection I4 screwed into the housing I3 and communicating with a passage I5 leading to a chamber I6 in the housing I3. From the chamber I6 passages I 'I and I8 lead to the annular groove I2 over an intermediate chamber I9. A handle formed as an internally screw threaded sleeve 20 is secured to the housing I 3 and extends substantially perpendicularly to the rod 8. The outer end of the sleeve 20 has secured therein a further sleeve 2I, the outer end of which is partially enclosed in a knob 22. The knob 22 is secured to a spindle 23 forming a valve control member and carrying a screw 24 meshing with internal screw threads in the sleeve 20 with so much play that air may escape along said threads from the chamber I6. A spring 25 is disposed in a bore 26 in the spindle 23, said spring serving to push the pressure reduction valve member 21 towards a seat formed at the opening of the passage I5 in the chamber I6. The stem 28 of said valve member is slidable in the bore 26, and it is easily understood that the pressure of the fluid in the chamber I6, which communicates with the feed leg through the passages I'I and I8, is reduced with respect to the pressure of the live air in the passage I5 by an amount corresponding to the amount the screw 24 is screwed out by means of the knob 22. When the spindle 23 is screwed all the way down, the spindle forces the valve member 2'I towards its seat by engaging an abutment on the valve member 21.

The sleeve 2| is provided with radial teeth 25J at the inner end surface of the sleeve, such teeth cooperating with radial teeth on a member 3|, which is rotatable and axially displaceable within the sleeve 20. The member 3| consequently forms a coupling with the toothed end of the sleeve 2 I. The member 3| is in constant engagement with a member 32 through two claws 33 on the member 32 engaging two corresponding recesses 34 in the member 3|. A spring 35 is inserted between an abutment in the sleeve 20 and an abutment on the member 3| and the spring 35 consequently acts to bring the teeth 33 into engagement with the teeth 29, so that the knob 22 may be arrested in any position of adjustment of the spindle 23. Air leaking from the chamber I6 through the threads of the screw 24 may flow through bores 36 in the spindle 23 through a passage 31 the opening of which is controlled by a spring-loaded ball valve 3S. A packing 33 prevents air leakage around the spindle 23, and, as soon as the valve 21 is opened and the screw 2d screwed out a certain distance, the spring load on the ball valve 38 forces said valve to seated position in which the ball valve prevents air leakage from the chamber I6 to the atmosphere.

A spring-loaded ball valve so actuated by a push button 4I is disposed in the intermediate chamber I9, and upon actuation of the push button 4| opens a passage 42 through which air may escape from the cylinder of the feed leg.

What we claim is:

1. A feeding mechanism for rock drills comprising an expansible pressure fluid operated feed leg, a supporting device on said feed leg for hingedly supporting a rock drill on the feed leg, a valve device for controlling the supply of pressure fluid to the feed leg, passages in said valve device for conducting pressure fiuid to the feed leg, a pressure reduction valve in said passages, a valve control member for setting said valve for different fluid pressures, and a coupling between said control member and a stationary part of the mechanism for arresting the control member in different positions of adjustment.

2. A feeding mechanism according to claim 1, in which the feed leg comprises a pair of telescopica-lly arranged members and the valve device and the supporting device are provided on one of said members, the valve device forming a handle n which the valve control member is journalled and in which the coupling is disposed.

3. A feeding mechanism according to claim l, in which the valve control member is rotatable in the valve device and the coupling consists of a toothed member rotatable with the valve control member and a second toothed member in the valve device which is engageable by said ro- 4 tatable toothed member for holding the valve control member in different positions of adjustment.

4. A feeding mechanism according to claim 3I in which the valve control member comprises a spindle on which the rotatable toothed member is non-rotatable but axially displaceable against spring action for disengaging the second toothed member.

5. A feeding mechanism according to claim l, in which the valve control member comprises a screw which forms an adjustable abutment for a spring-loaded valve and engages said valve in one extreme position of adjustment to press it towards a seat and close the pressure fluid supply to the feed leg.

6. A feeding mechanism for rock drills comprising an expansible pressure fluid operated feed leg, means for connecting said feed leg to a supporting device of a rock drill, a valve device on the feed leg for controlling the supply of pressure uid to the feed leg, passages in said valve device for conducting pressure fluid to the feed leg, a pressure reduction valve in said passages, a valve control member for setting said valve for different fluid pressures, and a coupling between said control member and a stationary part of the mechanism for arresting the control member in different positions of adjustment.

7. A controlling device for rock drill feeding mechanisms including a cylinder element, a piston rod and piston element movable therein under the infiuence of fluid pressure, and means for` hingedly connecting one of said elements to a rock drill, a housing on one of the elements, a first passage in said housing for supplying pressure fluid to the housing, a second passage in the housing for conveying pressure fluid to the element carrying the housing, a valve operable to control the flow of pressure fluid from said rst passage to said second passage and acted upon by the fluid pressure, a spring acting on said valve in opposite direction to said fluid pressure, a member for controlling the tension of said spring, and means for positively maintaining said control member in different positions of adjustment relatively to the housing for keeping said spring pressure at a desired adjusted value.

JAN AUGUST LARCE'N. svEN LAURENTIUS YTTERFORS.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,378,491 Stage May 17, 1921 2,097,561 Curtis Nov. 2, 1937 

